1968 quadrajet

[Brandon T.]

Can anybody tell me if the thin metal plate under the carburetor goes down on the intake or on the bottom or the carburetor. Also looking for someone that would be good at rebuilding it.

[Jim T.]

Re: 1968 quadrajet

Not at home to look and verify on my 1968, but I believe the stainless steel piece is on the intake.

[Lawrence M.]

Re: 1968 quadrajet

The gasket goes on the intake manifold and the thin stainless steel plate goes between the gasket and carb. The purpose of the stainless steel plate is to protect the carb base from the hot exhaust gases that are in that long slot in the manifold.

[Brandon T.]

Re: 1968 quadrajet

Thanks Lawrence, I had it on the intake and the gasket between it and the carb. Do know anybody that would do a good job rebuilding the carb?

[Brandon T.]

Re: 1968 quadrajet

The gasket goes on the intake manifold and the thin stainless steel plate goes between the gasket and carb. The purpose of the stainless steel plate is to protect the carb base from the hot exhaust gases that are in that long slot in the manifold.

I tried putting the plate between the gasket and the carb and it let the gases escape and sounded like a exhaut leak. The stainless steel plate has to go on top of the manifold to cover the long slot in the manifold. The gasket does not cover the long slot and if you put the plate on top of the gasket it leaves a opening so I had to put the stainless plat on top of the manifold to cover the long slot.

[Joe L.]

Re: 1968 quadrajet

I tried putting the plate between the gasket and the carb and it let the gases escape and sounded like a exhaut leak. The stainless steel plate has to go on top of the manifold to cover the long slot in the manifold. The gasket does not cover the long slot and if you put the plate on top of the gasket it leaves a opening so I had to put the stainless plat on top of the manifold to cover the long slot.

Brandon-----


That's not how it's supposed to be installed. The gasket goes on the manifold, then the stainless steel baffle, then the carburetor. If you get a leak with this arrangement, you've got some other problem.

I recommend that the heat slot in the manifold be disabled by installing drive plugs in the holes on either end. Your carburetor will last a lot longer with the heat slot disabled and you won't notice any problems doing so creates. GM eliminated the heat slot on all manifolds after 1969.

[Brandon T.]

Re: 1968 quadrajet

The gasket does not cover the hole on one side , maybe I have the wrong gasket on it.

[Lawrence M.]

Re: 1968 quadrajet



Brandon,
I got this pic off an auction site. Your carb gasket should look like this one. If you still get a leak with the gasket and baffle properly positoned you can put another gasket between the baffle and carb. I believe NAPA sells a gasket without the heat slot. As Joe said you should seal off the heat slot holes with plugs to protect the carb base plate.

[Brandon T.]

Re: 1968 quadrajet

I ordered a gasket set today that looks like your gasket. Looks like someone had the wrong gasket on it. I was told the stainless steel plate that goes between the gasket and carb would protect the carb. If i decide to plug the holes what type of plug should I use?

[Lawrence M.]

Re: 1968 quadrajet

You use 7/16 steel cup plugs. I got them from a local parts store that also had a machine shop. They look like tiny freeze plugs. Don't drive them in too far, just enough to seal that slot. The best way is pull the manifold and have a machine shop tap the holes for screw in plugs. The cup plugs worked for me until I had to pull the heads to be rebuilt. I then had the machine shop do the screw in plugs.

[Brandon T.]

Re: 1968 quadrajet

I will try to find some of those cup plugs, I don't want to tap the holes. Thanks for your help.

[Paul D.]

Re: 1968 quadrajet

Brandon, not trying to be a wise a** here, but you did notice that the gasket could be installed backwards I hope. One way covers the slot completely, one way doesn't and causes the exhaust leak. I'm not as certain about the plate, but I think the same applies to it. Look closely at the slot in the gasket and you will see it reaches out farther on one side. Chip.

[Joe L.]

Re: 1968 quadrajet

Brandon, not trying to be a wise a** here, but you did notice that the gasket could be installed backwards I hope. One way covers the slot completely, one way doesn't and causes the exhaust leak. I'm not as certain about the plate, but I think the same applies to it. Look closely at the slot in the gasket and you will see it reaches out farther on one side. Chip.

Chip------


Yup, very good point. The gasket and stainless steel baffle are NOT symmetrical and must be installed with the correct orientation. I thought that would be obvious to anyone installing them but maybe not.

[Brandon T.]

Re: 1968 quadrajet

I realize the stainless steel plate will only fit one way so it will cover the holes but someone put the wrong gasket on. That is why the metal baffle was installed on top of the intake so it would cover the holes. .The gasket was square and did not cover the holes. I have a new gasket kit ordered.

[Joseph K.]

Re: 1968 quadrajet

Brandon,

I purchased small freeze out plugs and inserted them in to the holes in the manifold. They fit perfectly They just need to be taped in lightly with a hammer. It protects the carb from the heat and also protects the lead seals on the bottom of the carb.